Sad indeed. But those are their lessons no matter how painful is for us to sit around and watch them do that to themselves.
Yup. It was very painful, especially so for my mother. It still is.
that's darwinism
the weak won't survive 
True. Anyone can live, but it takes more to survive and we all have our limits. Some higher, some lower. Please believe me when I say I am not offended by any of this. I am very much against such drugs and the loss of my younger brother is but one reason why. I am the one that turned him in for his use. I am the one that was called over and over again when he was in jail and later in the state hospital. He had threatened our mother and I would not tolerate the possibility of his threats being real.
My children love their uncle but his death has served a purpose that he would be proud of and that is to not mess around with this stuff. Once they were old enough to understand I sat them down and told them how he had died and the reason behind his death.